Novel lysophosphatidic acid receptor agonists and antagonists

ABSTRACT

The present invention is directed to compositions comprising lysophosphatidic acid analogs and methods of using such analogs as agonist or antagonists of LPA receptor activity. In addition the invention is directed to LPA receptor agonists that vary in the degree of selectivity at individual LPA receptors (i.e. LPA1, LPA2 and LPA3). More particularly the present invention is directed to LPA analogs wherein the glycerol is replaced with ethanolamine and a variety of substitutions have been linked at the second carbon atom.

[0001] This application claims priority under 35 U.S.C. §119(e) to provisional patent application No. 60/237,436 filed Oct. 3, 2000; 60/264,046 filed Jan. 25, 2001; and 60/297,507 filed Jun. 13, 2001, the disclosures of which are incorporated herein.

US GOVERNMENT RIGHTS

[0002] This invention was made with United States Government support under Grant Nos. NIH R01 GM52722, R01 CA88994, T32 GM07055 and NIH F31 DA05927 awarded by National Institutes of Health. The United States Government has certain rights in the invention.

FIELD OF THE INVENTION

[0003] The present invention is directed to compositions comprising lysophosphatidic acid analogs and methods of using such analogs as agonist or antagonists of LPA receptor activity. In addition the invention is directed to LPA receptor agonists that vary in the degree of selectivity at individual LPA receptors (i.e. LPA1, LPA2 and LPA3). Selective agonists and antagonists at LPA receptors will be useful therapeutically in a wide variety of human disorders.

BACKGROUND OF THE INVENTION

[0004] Lysophosphatidic acid (LPA, 1-acyl, 2-hydroxyl-sn-glycerol-3-phosphate) is an intermediary metabolite in all cells but is released from some cells to act as a mediator that elicits a wide variety of responses from cells/tissues. These responses include calcium mobilization, cytoskeletal rearrangements, mitogenesis and anti-apoptotic (survival) activity. For example, LPA is released by activated platelets and accumulates in serum to low micromolar levels, where it is a prominent growth factor for many cell types. LPA has also been found in ascitic fluid from ovarian cancer patients where it promotes mitogenesis of ovarian tumor cells. Interestingly, the LPA found in serum vs. ascitic fluid differs in that LPA from ascitic fluid is reportedly enriched in 2-acyl LPA species. Study of this 2-acyl LPA isoform is made difficult however by its chemical instability, i.e., the rapid migration of the acyl chain to the thermodynamically favored 1 position in an aqueous environment. Transient rises in blood pressure in rats and guinea pigs has also been documented following intravenous LPA injection. The induction of platelet aggregation and fibroblast recruitment along with its mitogenic capabilities implicate this lipid as a wound healing hormone.

[0005] LPA signals cells in part via a set of G protein-coupled receptors named LPA1, LPA2, and LPA3 (formerly Edg-2, Edg-4 and Edg-7). These receptors share 50-55% identical amino acids and cluster with five other receptors (S1P1, S1P2, S1P3, S1P4, S1P5 (formerly Edg-1, Edg-5, Edg-3, Edg-6, Edg-8) for the structurally-related lipid sphingosine 1-phosphate (S1P). LPA1 is most associated with activation of Giα pathways and is expressed in oligodendrocytes and peripheral tissues while LPA2 and LPA3 are associated most prominently with Gq/11α pathways. LPA2 mRNA is found in testis and peripheral blood leukocytes while LPA3 mRNA has been localized to prostate, testes, pancreas, kidney, and heart.

[0006] The physiologic implications of occupation of individual LPA receptors are largely unknown due in part to a lack of receptor type selective ligands. Therefore there is a need for compounds that have strong affinity and high selectivity for LPA receptors. The present invention is directed to a series of 2-substituted ethanolamide derivatives that vary in degrees of size, hydrophobicity, and stereochemistry. The parent compound of the claimed series, N-acyl ethanolamide phosphate (NAEPA) has been shown to be nearly indistinguishable from LPA in evoking platelet aggregation and GTP[γ 35 S] binding at LPA1 and LPA2 containing membranes but is distinctly less active than LPA at recombinant LPA3 or in depolarizing Xenopus oocytes.

[0007] Three 2-substituted NAEPA compounds have already been reported. A 2-carboxyl-containg compound (named ‘NASPA’ for N-palmitoyl serine phosphate) has been documented to antagonize both LPA-driven platelet aggregation (Sugiura et al., 1994 Arch Biochem Biophys 311: 358-368) and oocyte depolarization (Santos et al., 2000 NYAS Meeting Report; Annals New York Academy of Sciences p 232-241) and is a partial agonist at mammalian LPA receptors. A 2-methylene hydroxy-containing compound, which is an analog of 2-acyl LPA wherein the ester is replaced by an amide, has been reported as activating recombinant LPA receptors in a stereoselective fashion while mitogenic responses and platelet aggregation did not show this stereoselectivity. Finally, a third compound (named ‘PNPA’ for N-palmitoyl-norleucinol-1-phosphate) has n-butyl located at the 2 position. This compound aggregates human platelets without regard to stereoselectivity.

SUMMARY OF THE INVENTION

[0008] Starting with an LPA analog wherein the glycerol is replaced with ethanolamine (N-acyl ethanolamide phosphate, N-acyl EPA) as a lead structure a series of new chemical entities with a variety of substitutions at the second carbon atom were synthesized and tested for activity at the LPA receptors. LPA analogs were prepared and found to have a range of activities including agonism, with various degrees of selectivity at individual LPA receptors, as well as compounds with antagonist activity at the LPA receptors. More particularly, the LPA analogs of the present invention include compounds with the general structure:

[0009] wherein R₁ is a large lipophilic group, R₂ and R₃ are various substituents, n is an integer from 1-10, and R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, α-substituted methylene phosphonate, phosphate anlogs and phosphonate analogs. Selective agonists and antagonists at LPA receptors will be useful therapeutically in a wide variety of human disorders.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a graphic representation of the calcium mobilization in A431 cells treated with 10 μM of each compound. Columns 1-13 represent the administration of VPC12086, VPC12101, VPC12109, VPC122115, VPC12098, VPC12105, VPC12084, VPC12255, VPC31144, VPC31143, VPC31180, VPC31139 and LPA, respectively. 100% calcium indicates the signal observed after permeabilization with digitonin. Bars are representative of three experiments.

[0011] FIGS. 2A-2D are graphic representations of the effect of VPC12249 and VPC12204 on GTP[γ³⁵S] binding. GTP[γ³⁵S] binding assays of LPA1 (FIG. 2A), LPA2 (FIG. 2B), and LPA3 (FIG. 2C) transfected HEK293T cell membranes showing LPA concentration response curves with increasing concentrations of VPC12249. FIG. 2D shows the effect of VPC12204 (enantiomer of VPC12249) on GTP[γ³⁵S] binding at LP3 transfected HEK293T cell membranes. Points are in triplicate and are representative of at least two experiments.

[0012]FIG. 3 illustrates dose-response curves for LPA, VPC12031 and VPC12060 stimulation of GTPγ[³⁵S] in Rh7777 of HEK293T membranes at LPA1, LPA2, and LPA3 receptors. FIG. 3A represents stimulation of GTPγ[³⁵S] binding to LPA1 in Rh7777 membranes; FIG. 3B represents stimulation of GTPγ[³⁵S] binding to LPA2 in HEK293T membranes; FIG. 3C represents stimulation of GTPγ[³⁵S] binding to LPA3 in HEK293T membranes.

[0013]FIGS. 4A and 4B illustrate the inhibitory activity of NOHPP (VPC12031) and alpha keto NOHPP analog (VPC12060), respectively, at the LPP1 (PAP2a) phosphatase.

[0014]FIGS. 5A and 5B illustrate the inhibitory activity of NOHPP (VPC12031) and alpha keto NOHPP analog (VPC12060), respectively, at the LPP2 (PAP3a) phosphatase.

[0015]FIGS. 6A and 6B illustrate the inhibitory activity of NOHPP (VPC12031) and alpha keto NOHPP analog (VPC12060), respectively, at the LPP3 (PAP2b) phosphatase.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Definitions

[0017] In describing and claiming the invention, the following terminology will be used in accordance with the definitions set forth below.

[0018] As used herein, the term “purified” and like terms relate to the isolation of a molecule or compound in a form that is substantially free of contaminants normally associated with the molecule or compound in a native or natural environment.

[0019] As used herein, the term “treating” includes prophylaxis of the specific disorder or condition, or alleviation of the symptoms associated with a specific disorder or condition and/or preventing or eliminating said symptoms.

[0020] As used herein, an “effective amount” means an amount sufficient to produce a selected effect. For example, an effective amount of an LPA receptor antagonist is an amount that decreases the cell signaling activity of the LPA receptor.

[0021] As used herein, the term “halogen” means Cl, Br, F, and I. Especially preferred halogens include Cl, Br, and F. The term “haloalkyl” as used herein refers to a C₁-C₄ alkyl radical bearing at least one halogen substituent, for example, chloromethyl, fluoroethyl or trifluoromethyl and the like.

[0022] The term “C₁-C_(n) alkyl” wherein n is an integer, as used herein, represents a branched or linear alkyl group having from one to the specified number of carbon atoms. Typically C₁-C₆ alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl and the like.

[0023] The term “C₂-C_(n) alkenyl” wherein n is an integer, as used herein, represents an olefinically unsaturated branched or linear group having from 2 to the specified number of carbon atoms and at least one double bond. Examples of such groups include, but are not limited to, 1-propenyl, 2-propenyl, 1,3-butadienyl, 1-butenyl, hexenyl, pentenyl, and the like.

[0024] The term “C₂-C_(n) alkynyl” wherein n is an integer refers to an unsaturated branched or linear group having from 2 to the specified number of carbon atoms and at least one triple bond. Examples of such groups include, but are not limited to, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, and the like.

[0025] The term “C₃-C_(n) cycloalkyl” wherein n=4-8, represents cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.

[0026] As used herein, the term “optionally substituted” refers to from zero to four substituents, wherein the substituents are each independently selected. More preferredly, the term refers to from zero to three independently selected substituents. Each of the independently selected substituents may be the same or different than other substituents.

[0027] As used herein the term “aryl” refers to a mono- or bicyclic carbocyclic ring system having one or two aromatic rings including, but not limited to, phenyl, benzyl, naphthyl, tetrahydronaphthyl, indanyl, indenyl, and the like. Substituted aryl includes aryl compounds having one or two C₁-C₆ alkyl, halo or amino substituents. The term (C₅-C₈ alkyl)aryl refers to any aryl group which is attached to the parent moiety via the alkyl group.

[0028] The term “heterocyclic group” refers to a C₃-C₈ cycloalkyl group containing from one to three heteroatoms wherein the heteroatoms are selected from the group consisting of oxygen, sulfur, and nitrogen.

[0029] The term “bicyclic” represents either an unsaturated or saturated stable 7- to 12-membered bridged or fused bicyclic carbon ring. The bicyclic ring may be attached at any carbon atom which affords a stable structure. The term includes, but is not limited to, naphthyl, dicyclohexyl, dicyclohexenyl, and the like.

[0030] The terms 16:0, 18:0, 18:1, 20:4 or 22:6 hydrocarbon refers to a branched or straight alkyl or alkenyl group, wherein the first integer represents the total number of carbons in the group and the second integer represent the number of double bonds in the group.

[0031] The Invention

[0032] Lysophosphatidic acid (LPA) elicits a wide variety of responses from cells and tissues including calcium mobilization, changes in cell shape and motility, mitogenesis and anti-apoptosis. These effects are mediated by at least three LPA receptors (LPA1, LPA2 and LPA3) that have been cloned. Assignment of a physiological response to stimulation of a particular LPA receptor(s) is rmade difficult by lack of ligands that discriminate amongst receptor subtypes. The problem is exacerbated by the existence of at least three lyso-lipid phosphate phosphatases (LPPs) that act as ecto-phosphatases in degrading extra-cellular LPA as well as the potential for LPA to be acylated by LPA acyl transferases to yield another mediator, phosphatidic acid. Therefore, the discovery of new chemical entities that are (1) LPA receptor subtype selective agonists or antagonist and/or (2) LPA receptor agonists that are resistant to enzymatic degradation and/or (3) inhibitors of the LPPs is highly desirable.

[0033] A GTP[γ35 S] binding assay was developed to analyze directly the activation of individual LPA receptors, and thus allow the identification of LPA receptor agonists and antagonists as well as determine the relative efficacies and potencies at each receptor in a common system. The same results were obtained regardless of whether the recombinant receptor used exogenous G proteins (HEK293T cells) or endogenous G proteins (RH7777 cells) and further, the activities measured in the broken cell assay predicted the responses seen in whole cell assays. Thus the primary assay used in the present invention for compound potency and efficacy is a valid measure of activity at LPA/Edg receptors.

[0034] Starting with a LPA analog wherein the glycerol is replaced with ethanolaamine (N-acyl ethanolamide phosphate, N-acyl EPA) as a lead structure a series of new chemical entities with a variety of substitutions at the second carbon atom were synthesized and tested for activity at the LPA receptors. In particular, both the relative potency and efficacy of the 2-substituted N-acyl EPA compounds were measured. The 2-substituted N-acyl EPA compounds of the present invention include compounds having the general structure:

[0035] wherein R, is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, C₈-C₂₂ alkenoyl,

[0036] wherein m is 0-20;

[0037] Z is selected from the group consisting of C₃-C₁₀ cycloalkyl, C₃-C₁₅ bicycloalkyl, C₅-C₁₀ heterocyclic and aryl;

[0038] R₁₁ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₂₀ alkoxyl, C₁-C₂₀ alkylthio, and C₁-C₂₀ alkylamino;

[0039] R₂ and R₃ are independently selected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alcyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₁₀ alkyl)aryl, C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₈ alkyl)aryl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ alkynyl)aryl, and

[0040] wherein n is 0-10;

[0041] R₅ is selected from the group consisting of H and C₁-C₄ alkyl;

[0042] R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ aLkenyl)aryl, (C₂-C₁₂ alkyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0043] R₁₃ is selected from the group consisting of H, halo, C₁-C₁₀ alyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0044] wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkyl)R₇; and

[0045] R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl, wherein the ring structures are substituted with one or more substituents selected from the group of C₁-C₄ alkyl, C₁-C₄ alkoxyl, halo, amino or hydroxy groups;

[0046] y is 14; and

[0047] R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate, α-substituted methylene phosphonate, thiophosphate and phosphonate analogs.

[0048] In accordance with one embodiment the LPA analog has the general structure

[0049] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl,

[0050] wherein m is 0-20;

[0051] Z is selected from the group consisting of C₃-C₁₀ cycloalkyl, C₃-C₁₅ bicycloalkyl, C₅-C₁₀ heterocyclic and phenyl;

[0052] R₁₁ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₂₀ alkoxyl, C₁-C₂₀ alkylthio, and C₁-C₂₀ alkylamino;

[0053] R₂ and R₃ are independentlyselected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁—C₁₀ alkyl)aryl, C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₈ alkyl)aryl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ alkynyl)aryl, and

[0054] wherein n is 0-10;

[0055] R₅ is selected from the group consisting of H and C₁-C₄ alkyl;

[0056] R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0057] R₁₃ is selected from the group consisting of H, halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0058] wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkynyl)R₇; and

[0059] R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted aryl, wherein the ring structures are substituted with one or more substituents selected from the group of C₁-C₄ alkyl, C₁-C₄ alkoxyl, halo, amino or hydroxy groups; and

[0060] R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, α-substituted methylene phosphonate, thiophosphonate and phosphonate analogs. In one embodiment, R₁ is selected from the group consisting of

[0061] R₃ is H and R₄ is OPO₃ ⁻² or methylene phosphonate. Alternatively, R₁ is selected from the group consisting of

[0062] R₂ is H and R₄ is OPO₃ ⁻² or methylene phosphonate.

[0063] In another embodiment of the present invention the LPA analog is a compound represented by the structure:

[0064] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl, substituted C₈-C₂₂ alkyl and substituted C₈-C₂₂ alkenyl;

[0065] R₂ and R₃ are independently selected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₁₀ alkyl)aryl, C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₈ alkyl)azyl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ alkynyl)aryl, and

[0066] wherein n is 0-10;

[0067] R₅ is selected from the group consisting of H and C₁-C₄ alkyl;

[0068] R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0069] wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkynyl)R₇; and

[0070] R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl, wherein the ring structures are substituted with one or more substituents selected from the group of C₁-C₄ alkyl, C₁-C₄ alkoxyl, halo, amino or hydroxy groups; and

[0071] R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, α-substituted methylene phosphonate, thiophosphonate and phosphonate analogs.

[0072] In accordance with one embodiment, the LPA analogs of the present invention are represented by the structure:

[0073] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl;

[0074] R₂ and R₃ are independently selected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₁₀ alkyl)aryl, C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₈ alkyl)aryl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ alkynyl)aryl, and

[0075] R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate and α-substituted methylene phosphonate;

[0076] R₅ is selected from the group consisting of H and C₁-C₄ alkyl;

[0077] R₁₂ is selected from the group consisting of halo, C₁-C₆ alkyl, C₁-C₆ alkyl(C₅-C₈ cycloaLkenyl), C₁-C₆ alkenyl(C₅-C₈ cycloalkenyl), (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkenyl)OH, and OR₆;

[0078] R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ carboxy)R₇ —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇ and —(C₂-C₄ alkynyl)R₇; and

[0079] R₁ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted C₅-C₈ aryl, wherein the ring structures are substituted with one or more substituents selected from the group of C₁-C₄ alkyl, C₁-C₄ alkoxyl, halo, amino or hydroxy groups. In one embodiment, R₁ is C₁₃-C₁₇ alkyl or C₁₇-C₂₁, alkenyl, and R₃ is H. More preferably R₁ is a 15:0, 17:0, 17:1, 19:4 or 21:6 hydrocarbon, R₃ is H and R₄ is OPO₃ ⁻² or methylene phosphonate. The activities of various members of this series have been tested at the three LPA receptor subtypes and found to have LPA receptor agonist and antagonist activities.

[0080] One embodiment of the present invention is directed to the compounds of Formula II wherein R₁ is a 15:0, 17:0, 17:1, 19:4 or 21:6 hydrocarbon, R₃ is H, R₄ is OPO₃ ⁻² and R₂ is selected from the group consisting of 2-substitutions: methylene amino; para chloro benzyl; methylene benzyl; phenyl; methyl amino benzyl; aryl, and di-methyl. LPA analogs wherein R₄ is hydroxyl have not demonstrated activity as LPA receptor agonists or antagonists. However, it is anticipated that such compounds will be phosphorylated in vivo upon administration. Therefore compounds that have activity when R₄ is OPO₃ ⁻² may be formulated as prodrugs by substituting a hydroxyl group for OPO₃ ⁻² at R₄. In addition, the corresponding enantiomers are also encompassed by the present invention wherein R₁ is a 15:0, 17:0, 17:1, 19:4 or 21:6 hydrocarbon, R₂ is H, R₄ is OPO₃ ⁻² and R₃ is selected from the group consisting of 2-substitutions: methylene amino; para chloro benzyl; methylene benzyl; phenyl; methyl amino benzyl; aryl, and di-methyl. Additional compounds encompassed by the present invention include:

[0081] LPA is metabolized by a variety of conceivable routes including phosphatases, esterases and LPA acyl transferases or transported into cells. The LPA signal at receptors might be prolonged if the routes of degradation could be evaded or inhibited by LPA structural analogs. The LPA analogs of the present invention can be used, in accordance with one embodiment, to inhibit/evade endogenous LPA metabolic pathways including phosphotases, esterases, transporters and LPA acyl transferases. For example those LPA analogs of Formula I that lack and ester bond would be resistant to degradation by endogenous esterases. One embodiment of the present invention is directed to compounds that function as a LPA receptor agonists and antagonists that are resistant to hydrolysis by lyso-lipid phosphate phosphatases (LPPs) and are sub-type selective inhibitors of LPPs. Previously described LPA mimetics contain a phosphate group, and thus are likely susceptible to hydrolysis by LPPs. Furthermore, previously described LPA mimetics have not been shown to be selective for a particular LPA receptor.

[0082] Alpha hydroxy phosphonates are well known phosphate mimetics. For example, the compounds used clinically to treat osteoporosis (pamidronate, alendronate) are alpha hydroxy bisphosphonates that are analogs of pyrophosphate. LPA analogs were synthesized wherein the phosphate moiety is replaced by an alpha hydroxy phosphonate. Rather than being directly analogous to LPA, the LPP resistant compounds of the present invention are analogous to N-oleoyl ethanolamide phosphate—a compound that has been reported to be a potent, efficacious LPA mimetic. The structure of this compound, N-oleoyl-1-hydroxy propylamide phosphonic acid (NOHPP), is as follows:

[0083] The IUPAC name of NOHPP is (9Z)-N-(rac-3-hydroxy-3-phosphonopropyl)Octadec-9-enamide.

[0084] NOHPP inhibits LPP activity to varying degrees, and is a receptor subtype selective LPA mimetic. Specifically, NOHPP is fullly efficacious (compared to LPA) at the LPA1 and LPA2 receptors, but has little activity at the LPA3 receptor. NOHPP is about one log order less potent than 1-oleoyl LPA at both the LPA1 and LPA2 but greater than two log orders less potent at LPA3. Since the LPA receptor LPA3 has been reported to be less responsive to LPA with saturated acyl groups (Bandoh et al. (1999) J. Biol. Chem. vol. 274, pp.27776-27785), NOHPP with a palmitoyl group (16:0) might have even greater selectivity for LPA1 and LPA2 vs. LPA3. NOHPP inhibits LPP activities with rank order potency LPP3>LPP1>>LPP2. Furthermore, the LPA analogs of the present invention may function as LPP inhibitors even though they have poor agonist LPA activity. In accordance with one embodiment the LPP resistant compounds are used as selective inhibitors of LPP activity.

[0085] In addition, further derivatives of NOHPP are encompassed within the present invention wherein the amide linkage is replaced with a urea linkage, or an ethane or butane backbone is substituted for the propane backbone in NOHPP.

[0086] In accordance with one embodiment of the present invention a new series of compounds has been prepared that are analogous to N-oleoyl ethanolaride phosphate and are LPP resistant. These LPP resistant compounds have the general structure:

[0087] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, C₈-C₂₂ alkenoyl,

[0088] wherein m is 0-20;

[0089] Z is selected from the group consisting of C₃-C₁₀ cycloalkyl, C₃-C₁₅ bicycloalkyl, C₅-C₁₀ heterocyclic and phenyl;

[0090] R₁₁ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₂₀ alkoxyl, C₁-C₂₀ alkylthio, and C₁-C₂₀ alkylamino;

[0091] R₂ and R₃ are independently selected from the group consisting of H, hydroxy, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₄ alkyl)aryl, C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₁₀ alkyl)aryl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ alkynyl)aryl, and

[0092] wherein n is 0-10;

[0093] R₅ is selected from the group consisting of H and C₁-C₄ alkyl;

[0094] R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0095] R₁₃ is selected from the group consisting of H, halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0096] wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkynyl)R₇; and

[0097] R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl, wherein the ring structures are substituted with one or more substituents selected from the group of C₁-C₄ alkyl, C₁-C₄ alkoxyl, halo, amino or hydroxy groups;

[0098] q is 1-4

[0099] R₈ and R₉ are are independently selected from H, hydroxyl, amino, COOH, halo, —PO₃; or R₈ and R₉ taken together form a keto group or a methylene group; and

[0100] R₁₀ is selected from the group consisting of O, S and NH. In one embodiment, R₁ is C₈-C₂₂ alkanoyl or C₈-C₂₂ alkenoyl, R₂ is H, R₃ is hydroxy, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ akynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, or —COOR₅ and q is 1.

[0101] In one embodiment of the present invention the LPP resistant LPA analogs have the general structure:

[0102] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, substituted C₈-C₂₂ alkyl and substituted C₈-C₂₂ alkenyl;

[0103] R₂ and R₃ are independently selected from the group consisting of H, hydroxy, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₁₀ alkyl)aryl and

[0104] wherein n is 1-10;

[0105] R₅ is selected from the group consisting of H and C₁-C₄ alkyl;

[0106] R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NH₆ and OR₆;

[0107] wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkyyl, —(C₁-C₄ aLkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkyl)R₇; and

[0108] R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl, wherein the ring structures are substituted with one or more substituents selected from the group of C₁-C₄ alkyl, C₁-C₄ alkoxyl, halo, amino or hydroxy groups; and

[0109] R₈ and R₉ are independently selected from H, hydroxyl, amino, COOH, halo, —PO₃; or R₈ and R₉ taken together form a keto group or a methylene group.

[0110] In one embodiment of the present invention the LPP resistant LPA analogs have the general structure:

[0111] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl;

[0112] R₂ and R₃ are independently selected from the group consisting of H, hydroxy, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₄ alkyl)aryl and

[0113] wherein R₅ is H or C₁-C₄ alkyl;

[0114] R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkyl)R₇;

[0115] R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic and C₅-C₈ aryl; and

[0116] R₈ and R₉ are independently selected from the group consisting of H, hydroxyl, amino, COOH, halo, —PO₃; or R₈ and R₉ taken together form a keto group or a methylene group. In one embodiment, R₁ is C₁₃-C₁₇ alkyl or C₁₇-C₂₁ alkenyl, and more preferably R₁ is a 15:0, 17:0, 17:1, 19:4 or 21:6 hydrocarbon.

[0117] In one embodiment, the the LPP resistant LPA analog has the general structure

[0118] wherein R₁ is C₁₃-C₁₇ alkyl or C₁₇-C₂₁ alkenyl and R₈ and R₉ are independently selected from the group consisting of H, hydroxyl, fluoro, or R₈ and R₉ together form a keto group.

[0119] In another embodiment the compound has the general structure

[0120] wherein R₁ is C₁₄-C₁₈ alkyl or C₁₈-C₂₂ alkenyl;

[0121] R₂ and R₃ are independently selected from the group consisting of H, and

[0122] wherein R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkyl)R₇;

[0123] R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₂ bicyclic, C₅-C₈ cycloalkenyl and aryl; and

[0124] R₉ is selected from the group consisting of H, hydroxyl, halo, keto and —PO₃.

[0125] In accordance with one embodiment compounds of the present invention have the general structure:

[0126] wherein R₁ is C₈-C₂₂ alkyl or C₈-C₂₂ alkenyl;

[0127] R₂ is selected from the group consisting of C₁-C₆ alkyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, COOR₅, —(C₁-C₄ aLkyl)COOR₅, and —(C₁-C₄ alkyl)aryl; and

[0128] R₅ is selected from the group consisting of H and C₁-C₄ alkyl. In one preferred embodiment R₁ is C₁₃-C₁₇ alkyl or C₁₇-C₂₁ alkenyl, and R₂ is C₁-C₄ alkyl, methylene hydroxyl, carbomethyl, methylene amino or benzyl.

[0129] In one embodiment compounds that are based on the structure of NOHPP and fall within the scope of the present invention include the following compounds:

[0130] One aspect of the present invention is directed to the NOHPP analog, w1s-b8L. The IUPAC name for w1s-b8L is: (9Z)-N-(3-phosphonopropyl)Octadec-9-enamide, and the trivial name is oleoylaminopropylphosphonate. The structure of w1s-b8L is shown below:

[0131] w1s-b8L is expected to be resistant to hydrolysis by phosphohydrolases by virtue of its containing a phosphonate, rather than a phosphate, group. Furthermore this chemical entity (w1s-b8L) has two additional desirable properties. Firstly, w1s-b8L is distinctly more selective regarding its agonist activity at a single LPA receptor (LPA1) than VPC12031 (the alpha hydroxy analog of NOHPP) and VPC12060 (the alpha keto analog of NOHPP) and, secondly, at concentrations up to 10 micromolar, w1s-b8L does not elicit aggregation of human platelets.

[0132] The novel LPA receptor agonists disclosed in the present invention are anticipated to have utility in a variety of clinical settings including but not limited to the acceleration of wound healing (including corneal wounds), the promotion of myelination (oligodendrocyte cell function) and for immuno-modulation. In particular, LPA has been reported (Balazs et al. Am J Physiol Regul Integr Comp Physiol, 2001 280(2):R466-472) as having activity in accelerating wound closing and increasing neoepithelial thickness. Accordingly, one embodiment of the present invention comprises administering a pharmaceutical composition comprising one or more of the LPA receptor agonists of the present invention to a mammalian species (including humans) to treat a wound, improve neuronal function or enhance an immune response of that species. LPA has been demonstrated to induce a modest dose-dependent increase in proliferating cells, and a marked increase in the immigration of histiocyte-macrophage cells. Accordingly, in one embodiment compositions comprising an LPA receptor agonist is used to treat wounds, including burns, cuts, lacerations, surgical incisions, bed sores, and slow-healing ulcers such as those seen in diabetics. In one preferred embodiment a composition comprising an LPA agonist is administered to a patient to enhance wound repair. Typically the composition is administered locally as a topical formulation, however other standard routes of administration are also acceptable.

[0133] The investigation of various 2-substitutions revealed several trends (see Example 2, Table 1) in a series of compounds having the general structure of Formula I, wherein R₁ is a 17:1 hydrocarbon and R₄ is OPO₃ ⁻². First, each LPA receptor showed a marked (one log order or more) preference for one enantiomer. Second, most substitutions were well tolerated in that they resulted in agonist ligands. Third, the LPA3 receptor, unlike LPA1 and LPA2, differentiates between unsaturated and saturated acyl groups and that LPA3 appears to have a lower affinity for LPA and LPA analogs.

[0134] Although most active compounds were partial agonists with reduced potency (relative to LPA), the R-methyl compound (VPC12086) is notable in that it is more potent and efficacious than LPA at LPA₁. A pattern observed with all three LPA receptors was that the R configuration was more potent with all substituents, an exception is VPC31139, which is more active in the S configuration. These data indicate that each receptor has a single spatial region within the ligand binding site.

[0135] In accordance with one embodiment an LPA receptor agonist is provided having the general structure

[0136] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, substituted C₈-C₂₂ alkyl and substituted C₈-C₂₂ alkenyl;

[0137] R₂ is selected from the group consisting of C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —(C₁-C₄ alkyl)COOR₅, and —(C₀-C₁₀ alkyl)aryl;

[0138] R₄ is selected from the group consisting of hydroxyl, phosphate, thiophosphate, methylene phosphonate and a substituted methylene phosphonate; and

[0139] R₅ is selected from the group consisting of H and C₁-C₄ alkyl.

[0140] In one embodiment the compound has the general structure:

[0141] wherein R₁ is a saturated or unsaturated, substituted or non-substituted, straight or branched chain alkyl of about 8 to 22 carbon atoms where the #1 carbon may be in the form of a carbonyl group (C═O), i.e. the alkyl chain is joined by an amide linkage. In certain embodiments, RX is oleic acid (18:1) or palmitic acid (16:0) combined in an amide linkage; R₂ is methyl, ethyl, propyl, isopropyl, butyl, methylene hydroxy, methylene amino, methylene alkyne, phenyl, benzyl, methylene furan, methylene-2-naphthalene; and R₄ is hydroxyl (OH), phosphate (PO₄), or methylene phosphonate (CH₂PO₃). When R₄ is methylene phosphonate, the carbon alpha to the phosphorus can be optionally substituted with an hydroxyl, keto, fluoro or phosphonate moieties or di-substituted with fluoro or hydroxy and phosphonate substituents.

[0142] In accordance with one embodiment the LPA receptor agonist is provided having the general structure:

[0143] wherein R₂ is methyl, ethyl, propyl, isopropyl, butyl, methylene hydroxy, methylene amino, methylene aLlcyne, phenyl, benzyl, methylene furan, methylene-2-naphthalene; and R₄ is hydroxyl (OH), phosphate (PO₄), or methylene phosphonate (CH₂PO₃).

[0144] In accordance with one embodiment of the present invention LPA receptor subtype-selective compounds having agonist and/or antagonist properties can be administered to a subject to treat or prevent a disorder of abnormal cell growth and differentiation. These disorders include, but are not limited to, Alzheimer's disease, aberrant corpus luteum formation, osteoarthritis, osteoporosis, anovulation, Parkinson's disease, multiple sclerosis and rheumatoid arthritis.

[0145] As noted above LPA3 has a lower affinity for LPA and LPA analogs. It is believed that LPA3 may play a role in feedback inhibition of activity at LPA 1 and LPA2. Therefore it is anticipated that an LPA3 subtype-selective agonist can be used to decrease LPA1 and LPA2 mediated activities. Thus in accordance with one embodiment an LPA3 subtype-selective agonist can be administered to a subject to treat or prevent a disorder of abnormal cell growth and differentiation, including cancer. To be considered a subtype selective agonist/antagonist, the compound mus be 10× more potent, and more preferably 100× more potent, at the preferred LPA receptor. For example, it appears that mono-unsaturated substituents at R₁ of the LPA receptor analogs of Formula I are significantly more potent (equipotent to LPA) than the saturated compound at LPA3. LPA1 and LPA2 do not exhibit this selectivity for unsaturated vs. saturated side chains.

[0146] Similarly LPA receptor antagonist can also be used to inhibit LPA mediated activities and thus treat disorders of abnormal cell growth and differentiation as well as inflammatory diseases. These disorders include, but are not limited to, Alzheimer's disease, aberrant corpus luteum formation, osteoarthritis, osteoporosis, anovulation, Parkinson's disease, multiple sclerosis, rheumatoid arthritis and treatment of cancer. Such antagonists can then be formulated as pharmaceutical compositions using standard pharmaceutically acceptable carriers, fillers, solublizing agents and stabilizers known to those skilled in the art. Pharmaceutical compositions comprising the LPA receptor subtype-selective agonist and/or antagonist are administered to an individual in need thereof by any number of routes including, but not limited to, topical, oral, intravenous, intramuscular, intra-arterial, intramedullary, intrathecal, intraventricular, transdermal, subcutaneous, intraperitoneal, intranasal, enteral, topical, sublingual, or rectal means.

[0147] In accordance with one embodiment LPA receptor antagonists are provided, wherein the antagonists have the general structure

[0148] wherein R₁ is selected from the group consisting of C₈-C₂₂ allyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, C₈-C₂₂ alkenoyl,

[0149] wherein m is 0-20;

[0150] Z is selected from the group consisting of C₃-C₁₀ cycloalkyl, C₃-C₁₅ bicycloalkyl, C₅-C₁₀ heterocyclic and phenyl;

[0151] R₁₁ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₂₀ alkoxyl, C₁-C₂₀ alkylthio, and C₁-C₂₀ alkylamino;

[0152] R₂ and R₃ are independently selected from the group consisting of H, and

[0153] wherein n is 0-10;

[0154] R₁₂ is selected from the group consisting of C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆;

[0155] R₁₃ is selected from the group consisting of H, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ aLkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, phenyl-4-methoxy, SR₆, SOR₆, NHR₆ and OR₆;

[0156] wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkynyl)R₇;

[0157] R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic, optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl; and

[0158] R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, α-substituted methylene phosphonate, thiophosphonate and phosphonate analogs. In one preferred embodiment n is 1, R₁₃ is H and R₁₂ is SR₆, SOR₆, NHR₆ or OR₆.

[0159] In accordance with one embodiment LPA receptor antagonists are provided, wherein the antagonists have the general structure

[0160] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, substituted C₈-C₂₂ alkyl and substituted C₈-C₂₂ alkenyl;

[0161] R₂ and R₃ are independently selected from the group consisting of H, and

[0162] wherein R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkenyl)R₇, —(C₂-C₄ alkynyl)R₇ and —(C₂-C₄ alkyl)R₇;

[0163] R₇ is

[0164] wherein R₁₄ and R₁₅ are independently selected from the group consisting of H, C₁-C₁₂ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, halo; and

[0165] R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, with the proviso that R₂ and R₃ are not both H. In one embodiment, R₁ is C₁₃-C₁₇alkyl or C₁₇-C₂₁ alkenyl and R₄ is phosphate or methylene phosphonate. More preferably R₁ is a 15:0, 17:0, 17:1, 19:4 or 21:6 hydrocarbon and R₄ is phosphate.

[0166] In accordance with one embodiment the LPA receptor antagonist has the general structure:

[0167] wherein R₂ and R₃ are independently selected from the group consisting of H, benzyl, methylene furan, methylene-2-naphthalene, methylene phenyl-4-O-benzyl, methylene phenyl-4-benzyl, methylene phenyl-4-chloro, methylene phenyl-4-trans-styrene, methylene phenyl-4-cis-styrene, methylene phenyl-4-O-2,6-dichlorobenzyl and methylene phenyl-4-phenyl. In one preferred embodiment R₂ is H.

[0168] Additional compounds that serve as antagonists of LPA receptor function include compounds of the general formula:

[0169] wherein R₃ is selected from the group: Compound name and Stereochemistry (R) (S)

VPC12204 VPC12249

VPC12250 VPC12229

VPC12193 VPC12227

VPC12235 VPC12228

VPC12284

VPC13061 VPC13082

VPC13063 VPC13086

VPC13066

VPC13069 VPC13089

[0170] One example of an LPA antagonist in accordance with the present invention is VPC12249. That compound, having the backbone structure of Formula II, wherein R₁ is a 17:1 hydrocarbon, R₂ is H, R₄ is OPO₃ ⁻² and R₃ contains the benzyl-4-oxybenzyl functionality in the S-configuration, which confers antagonistic activity at LPA1 and LPA3 receptors. VPC12249, to our knowledge, is the first specific LPA1/LPA3 receptor antagonist. This compound possesses high affinity for the LPA1 (ca. KI=130 nM) and LPA3 (ca. KI=425 nM) receptors. In addition compound VPC31162 (structure of Formula II, wherein R₁ is a 17:1 hydrocarbon, R₂ is H, R₄ is OPO₃ ⁻² and R₃ is benzyl-4-oxybenzyl-4-pentane) has antagonist activity at the LPA2 receptor, but is an agonist at LPA1 and LPA3.

[0171] In accordance with one embodiment of the present invention the LPA analogs that exhibit LPA receptor antagonist activity can be used to treat ischemia reperfusion type injury. Interference with the supply of oxygenated blood to tissues is defined as ischemia. The effects of ischemia are known to be progressive, such that over time cellular vitality continues to deteriorate and tissues become necrotic. Total persistent ischemia, with limited oxygen perfusion of tissues, results in cell death and eventually in coagulation-induced necrosis despite reperfusion with arterial blood. A substantial body of evidence indicates that a significant proportion of the injury associated with ischemia is a consequence of the events associated with reperfusion of ischemic tissues, hence the term reperfusion injury.

[0172] To place reperfusion injury into a clinical perspective, there are three different degrees of cell injury, depending on the duration of ischemia: (1) With short periods of ischemia, reperfusion (and resupply of oxygen) completely restores the structural and functional integrity of the cell. Whatever degree of injury the cells have incurred can be completely reversed upon reoxygenation. (2) With longer periods of ischemia, reperfusion is not associated with the restoration of cell structure and function, but rather with deterioration and death of cells. The response to reoxygenation in this case is rapid and intense inflammation. (3) Lethal cell injury may develop during prolonged periods of ischemia, where reperfusion is not a factor. The reversibility of cell injury as a consequence of ischemia is determined not only by the type and duration of the injury, but also by the cell target. Neurons exhibit very high sensitivity to ischemia, whereas myocardial, pulmonary, hepatic and renal tissues are intermediate in sensitivity. Fibroblasts, epidermis and skeletal muscle have the lowest susceptibility to ischemic injury, requiring several hours without blood supply to develop irreversible damage.

[0173] In accordance with the present invention a compound having the general structure:

[0174] wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, substituted C₈-C₂₂ alkyl and substituted C₁-C₂₂ alkenyl;

[0175] R₂ and R₃ are independently selected from the group consisting of H, and

[0176] wherein R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkenyl)R₇, —(C₂-C₄ alkynyl)R₇ and —(C₂-C₄ alkyl)R₇;

[0177] R₇ is

[0178] wherein R₁₄ and R₁₅ are independently selected from the group consisting of H, C₁-C₁₂ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, halo; and

[0179] R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, with the proviso that R₂ and R₃ are not both H is administered to reduce of prevent reperfusion injury. In one embodiment, R₁ is C₁₃-C₁₇alkyl or C₁₇-C₂₁ alkenyl and R₄ is phosphate or methylene phosphonate. More preferably R₁ is a 15:0, 17:0, 17:1, 19:4 or 21:6 hydrocarbon and & is phosphate. In one preferred embodiment the compound is VPC12249.

[0180] The LPA receptor antagonist of the present invention can be formulated with pharmaceutically acceptable carriers, diluents, and solubilizing agents for administration to patient in need of such therapy. The compounds are preferably administered intravenously, but any standard route of administration is acceptable including oral delivery. In particular, if the LPA receptor antagonist is administered prior to tissue injury, such as to a patient prior to surgery, the LPA receptor antagonist can be administered orally.

[0181] Preferably, a therapeutically effective amount of the LPA receptor antagonist is administered intravenously in a physiologically acceptable carrier as early as possible, and most preferably within four hours of a reperfusion injury. Subsequent doses of the LPA receptor antagonist, can be administered intravenously or orally.

Example 1 Synthesis of 2-Substituted, Ethanolamide-Based LPA Analogs

[0182] Chemicals for syntheses were purchased from Aldrich Chemical Company, Inc., Sigina Chemical Company, Inc., Advanced ChemTech Chemical Company, Inc. and/or NovaBiochem Chemical Company, Inc., and were used without further purification. The general approach used to synthesize the LPA analogs of the present invention is shown in Scheme 1. Briefly the seven steps are as follows:

[0183] General Procedure A: Installation of Chiral Auxillary

[0184] To a solution of carbobenzyloxy-protected amino acid in diethyl ether at −78° C. is added triethylamine followed by pivaloyl chloride. The resulting thick white precipitate is stirred for 1 hr at 0° C. and then re-cooled to −78° C. In a separate flask, a solution of [4S]4benzyl-2-oxaxolidinone in tetrahydrofuran (THF) is prepared. On cooling this solution to −78° C., n-butyllithium is added via a syringe over 5 minutes. The resulting solution is cannulated to the flask containing the mixed anhydride. The mixture is stirred for 15 min at −78° C. and 30 min at 0° C. before quenching by addition of aqueous ammonium chloride. The resulting solution is concentrated and diluted with methylene chloride, extracted (3×) with sodium bicarbonate and brine and dried (Na₂SO₄). The imide product is isolated by flash chromatography.

[0185] General Procedure B: Alpha-Carbon Alkylation

[0186] To a solution of imide in dichloromethane at 0° C. is added titanium tetrachloride. After stirring for 5 minutes, diisopropylethylamine is added. The solution is stirred for 3 hours at 0° C., and then the alkylbromide is added. The resulting solution is stirred for an additional 2 hours before cannulated to a vigorously stirring mixture of saturated aqueous sodium bicarbonate. The layers are separated and extracted (three times) with dichloromethane, dried (Na₂SO₄) and concentrated. The α,α-substituted product is isolated by flash chromatography.

[0187] General Procedure C: Chiral Auxilliary Removal

[0188] To a solution of α,α-substituted amino acid in TBF at 0° C. is added methanol and lithium borohydride. The solution is stirred for 1 hour and quenched by the addition of 1.0M sodium potassium tartrate and stirring for 10 min at 0° C. The layers are separated and extracted (3×) with dichloromethane, dried (Na₂SO₄) and concentrated. The alcohol product is isolated by flash chromatography.

[0189] General Procedure D: Phosphorylation

[0190] To a solution of alcohol in 1:1 THF/CH₂Cl₂ in an aluminum foil covered round bottom flask is added tetrazole. After stirring for 15 minutes, di-t-butyldiisoproylphosphoramidite is added. The solution is stirred for 6 hours and quenched with sodium metabisulfite at 0° C., and extracted with ethylacetate. The organic layers are combined dried (Na₂SO₄) and concentrated. The product is purified by flash chromatography.

[0191] General Procedure E: N-Cbz Deprotection

[0192] To a solution of Cbz-protected phosphate in ethanol is added 10% Pd/C. The resulting solution is placed under H₂ atmosphere. After 2 hours, the solution is filtered and concentrated to provide the product.

[0193] General Procedure F: Addition of Fatty Acid Moiety

[0194] To a solution of amine in dichloromethane is added N,N-diisopropylethylamine. After stirring for 10 minutes, oleoyl chloride is added via a syringe over 20 minutes. The resulting solution is quenched by adding saturated aqueous ammonium chloride after 1 hour. The aqueous layer is extracted (3×) with ethyl acetate and the combined organic layers are dried (Na₂SO₄) and concentrated. The product is purified by flash chromatography.

[0195] General Procedure G: Phosphate Deprotection

[0196] To a solution of protected phosphate in dichloromethane is added trifluoroacetic acid. After 2 hours, the solvent is removed via rotary evaporation and ether is added and removed. This process is repeated until the all trifluoroacetic acid is removed, providing the phosphate deprotected product.

[0197] Additional synthetic details are provided in the following:

[0198] Reagents: (a) i. DIEA, isobutylchloroformate, ii. NaBH₄, H₂O; (b) 1H-Tetrazole, N,N-di-t-butyl diisopropylphosphoramidite; (c) 10% Pd/C, H₂; (d) Oleoyl chloride, DIEA or pyridine; (e) 1:1 TFA/CH₂Cl₂

[0199] Reagents: (a) Oleoyl chloride, DIEA or pyridine; (b) 1H-Tetrazole, N,N-di-t-butyl diisopropylphosphoramidite; (c) 1:1 TFA/CH₂Cl₂

[0200] Reagents: (a) i. DIEA, isobutylchloroformate, ii. NaBH₄, H₂O; (b) i. 1:1 TFA/CH₂Cl₂; ii. Oleoyl chloride, DIEA or pyridine; (c) 1H-Tetrazole, N,N-di-t-butyl diisopropylphosphoramidite; (d) 10% Pd/C, H₂; (e) 1:1 TFA/CH₂Cl₂

[0201] Reagents: (a) i. DIEA, isobutylchloroformate, ii. NaBH₄, H₂O; (b) 1H-Tetrazole, N,N-1-t-butyl diisopropylphosphoramidite; (b) i. 1:1 DIEA/CH₂Cl₂; ii. Oleoyl chloride; (d) 1:1 TFA/CH₂Cl₂

[0202] Reagents: (a) BnNH₂, NaBH₃CN, MeOH; (b) 15% Pd(OH)₂, H₂; (c) i. Fmoc-Cl, NaHCO₃, THF/H₂O; ii. 1:1 TFA/CH₂Cl₂, then HCl; (d) Oleoyl chloride, DIEA; (e) 1H-Tetrazole, N,N-di-t-butyl diisopropylphosphoramidite; (f) i. piperidine, DMF; ii. 1:1 TFA/CH₂Cl₂

Example 2 Activity of 2-Substituted LPA Analogs at Edg/LPA Receptors

[0203] Materials and Methods

[0204] Transient Expression in HEK293T Cells

[0205] The appropriate receptor plasmid DNA (encoding mouse LPA1, human LPA2 or human LPA3) was mixed with equal amounts of expression plasmids (pcDNA3) encoding a mutated (C351 F) rat Gi2a, cow β1, and γ2 proteins and these DNAs were used to transfect monolayers of HEK293T cells (where ‘T’ indicates expression of the SV-40 virus large T antigen) using the calcium phosphate precipitate method. After about 60 hours, cells were harvested, membranes were prepared, aliquoted and stored at −70° C. until use.

[0206] GTP[35 γS] Binding:

[0207] The GTP[35 γS] assay was performed as described by us previously. Membranes containing 5 ug of protein were incubated in 0.1 ml GTP-binding buffer (in mM: HEPES 50, NaCl 100, MgCl₂ 10, pH7.5) containing 5 mg saponin, 10 mM GDP, 0.1 nM GTP[35 γS] (1200 Ci/mmol), and indicated lipid(s) for 30 minutes at 30° C. Samples were analyzed for membrane-bound radionuclide using a Brandel Cell Harvester (Gaithersburg, Md.). The C351F mutation renders the Gi2α protein resistant to inactivation by pertussis toxin or the alkylating agent N-ethylmaleimide; however in practice background binding was sufficiently low to obviate these maneuvers.

[0208] Measurement of cAMP Accumulation:

[0209] Assays for cAMP accumulation were conducted on populations of 5×10⁵ cells stimulated with 10 mM forskolin in the presence of the phosphodiesterase inhibitor isomethylbutylxanthine (IBMX) for 15 minutes at 30° C. cAMP was measured by automated radioimmunoassay.

[0210] Measurement of Intracellular Calcium:

[0211] A FLIPR™ (Molecular Devices, Inc.) was used to measure intracellular calcium in A431 and HEK293T cells. A431 cells were seeded (˜50,000 cells/well) in 96-well clear bottom black microplates (Corning Costar Corp., Cambridge, Mass.) and left overnight in CO₂ incubator at 37° C. HEK293T cells were treated likewise, but seeded onto poly D-lysine coated microplates (Becton Dickinson, Franklin Lakes, N.J.). A431 cells were dye-loaded with 4 μM Fluo-3 AM ester (Molecular Probes Inc., Eugene, Oreg.) in a loading buffer (1× HBSS buffer, pH 7.4, containing 20 mM HEPES, 0.1% BSA, and 2.5 mM probenecid) for 1 hour at 37° C. Cells were then washed four times with the loading buffer and exposed in the FLIPR™ to sets of compounds. HEK293T cells were loaded with 2 μM Fluo4 AM ester (Molecular Probes Inc., Eugene, Oreg.) in the same loading buffer without probenecid for 30 minutes and washed four times before being exposed to compounds in the FLIPR™. In all cases, each concentration of each compound was tested in at least quintuplicate.

[0212] Determination of KI:

[0213]KI for VPC12249 in experiments were determined by plotting the log of Dose Ratio-1 at each concentration of inhibitor against the log concentration of inhibitor. The X-intercept of the linear transformation is equal to the inverse log of the KI.

[0214] Stable Expression In RH7777 Cells:

[0215] Rat hepatoma RH7777 cell monolayers were transfected with the mLPAI plasmid DNA using the calcium phosphate precipitate method and clonal populations expressing the neomycin phosphotransferase gene were selected by addition of geneticin (G418) to the culture media. The RH7777 cells were grown in monolayers at 37° C. in a 5% CO₀2/95% air atmosphere in growth media consisting of: 90% MEM, 10% fetal bovine serum, 2 mM glutamine and 1 mM sodium pyruvate.

[0216] Cardiovascular Measurements:

[0217] All procedures were performed on Male Wistar rats in accordance with National Institutes of Health and University of Virginia animal care and usage guidelines. Anesthesia was induced by 5% halothane (in 100% O₂). Rats were intubated and artificially ventilated with 1.5-1.8% halothane in 100% O₂ for surgical procedures. A femoral artery was cannulated to record mean arterial pressure (MAP) and heart rate (HR), and a femoral vein was cannulated to administer anesthetic agents. A femoral vein was cannulated for administration of lipids. The left splanchnic nerve was isolated via a retroperitoneal approach, and the segment distal to the suprarenal ganglion was placed on two Teflon-coated silver wires that had been bared at the tip (250 mm bare diameter; A-M Systems, Everett, Wash.). The nerve and wires were embedded in a dental impression material (polyvinysiloxane; Darby Dental Supply, Westbury, N.Y.), and the wound was closed around the exiting recording wires. On completion of surgery, the halothane anesthesia was terminated and was replaced by a α-chloralose (30 mg/kg solution in 3% sodium borate; 70 mg/kg initial bolus followed by hourly supplements of 20 mg/kg iv; Fisher Scientific, Pittsburgh, Pa.). Rats were allowed to stabilize for 45 min before tests began. End-tidal CO₂ was monitored by infrared spectroscopy and was maintained between 3.5 and 4.0%. Body temperature (measured rectally) was maintained at 37° C.

[0218] All physiological variables were monitored on a chart recorder (model RS 3600, Gould, Valley View, Ohio) and simultaneously stored on a videocassette recorder via a digitizer interface (model 3000A, frequency range: DC-22 kHz; Vetter Digital, Rebersburg, Va.) for off-line computer analysis. Data was analyzed with Spike 2 (Cambridge Electronics). The MAP was calculated from the pulse pressure measured by a transducer (Statham P10 EZ, Gould) connected to the brachial arterial catheter. The HR was determiined by triggering from the pulse pressure (Biotach, Gould). Splanchnic nerve activity (SNA) was filtered (10 Hz-3 kHz band pass with a 60-Hz notch filter), full-wave rectified, and averaged in 1-s bins. The femoral venous catheter (dead space 100 mL) was loaded with each lipid and was flushed with 200 mL of saline to expel the drug.

[0219] Materials: Chemicals for syntheses were purchased from Aldrich Chemical Company, Inc., Sigma Chemical Company, Inc., Advanced ChemTech Chemical Company, Inc. and/or NovaBiochem Chemical Company, Inc., and were used without further purification. GTP[γ 35 S] was purchased from Amerhsam, Fura-3 and Fura-4 AM were purchased from Molecular Probes Inc., A431 and RH7777 cells were purchased from the American Type Culture Collection (Manassas, Va.) and tissue culture media and serum was from GibcoBRL/Life Technologies (Gaithersburg, Md.). HEK293T cells were a gift from Dr. Judy White's laboratory (Dept. Cell Biology, University of Virginia) while G protein β and γ DNAs were a gift from Dr. Doug Bayliss (Dept. Pharmacology, University of Virginia). LPAs (1-oleoyl and 1-palmitoyl) and dioctyl glyceryl pyrophosphate were purchased from Avanti Polar Lipids (Alabaster, Ala.).

[0220] Results:

[0221] Using N-oleoyl ethanolamide phosphoric acid (NAEPA) as a lead structure, a series of 2-substituted LPA analogs was synthesized. The details of the synthesis and analysis of the full set of compounds in this series is described in Example 2. Each compound was characterized by 1 H NMR, 13C NMR, and mass spectrometry.

[0222] The differential coupling of LPA1 versus LPA2 and LPA3, the lack of a reliable radioligand binding assay, and the near ubiquity of endogenous LPA responses prohibited the use of most common receptor assay techniques (i.e. measurements of adenylyl cyclase activity, calcium mobilization, radioligand binding) to assess each compound's activity. Therefore, we adapted a GTP[γ 35 S] binding assay to measure the relative efficacies and potencies of each compound compared to LPA. This assay isolates each recombinant LPA receptor and allows analysis of all three receptors using the same system. Note that membranes from HEK293T cells transfected with only G protein DNAs (i.e., no receptor DNA) were devoid of LPA-stimulated GTP binding despite expressing endogenous LPA receptors.

[0223] Many NAEPA compounds with various 2-substituents were synthesized and examined. Since the 2 position is a prochiral site, both enantiomers of the eight compounds were synthesized. Three patterns were revealed when the agonist compounds were tested in this series at the three LPA receptors in the broken cell assay. First, each LPA receptor showed a marked (one log order or more) selectivity for one enantiomer. Second, those compounds with substitutions at the R2 position of Formula I were invariably the more potent agonists. Third, agonist potency decreases as the bulk of the substituent increases. The 2-substituted NAEPA compounds containing either hydrophilic (methylene hydroxy, carbomethyl, methylene amino) or hydrophobic moieties (methyl, ethyl, isopropyl, benzyl) exhibited agonist activity in the GTP[γ 35 S] binding assay (see Table 1). The smaller groups conferred greater potency, with the methyl (VPC12086), methylene hydroxy (VPC31143) and methylene amino (VPC12178) compounds being more potent than 1-oleoyl LPA at LPA1 (Table 1). Also, as the 2-substituent becomes bulkier, the efficacy was noticeably reduced at this receptor. In contrast, bulkier hydrophobic side chains, although less potent, were fully efficacious at the LPA2 receptor (Table 1). TABLE 1 Agonist activities of 2-substituted N-oleoyl EPA compounds LP A1 LP A2 LP A3 Functional EC50 EC50 EC50 Lipid Group (nM) Emax (nM) Emax (nM) Emax LPA 11.7 100 6.8 100 262.5 100 31143 Methylene 7.9 161.4 116.5 104.6 321.8 106.6 Hydroxy 31144 Methylene >5000 91.1 2645 77.3 4349 N/A Hydroxy 31139 Carbo 18.5 66.2 29.2 91.3 1484 84.4 Methyl 31180 Carbo 1215 50.6 3461 60.2 >5000 3.8 Methyl 12178 Methylene 4.9 98.7 50.3 103.2 683.7 102.9 Amino 12048 Methylene >5000 9.4 >5000 36.4 >5000 3.8 Amino 12086 Methyl 3.4 107.6 18.3 95.2 112.6 93.4 12101 ″ 2900 48.1 >5000 6.9 >5000 9.7 12109 Ethyl 35.8 66.8 161.9 92.6 1083 83.5 12115 ″ 1580 62.3 4280 85.6 4980 89.3 12098 Isopropyl 73.8 51 799.3 85.8 3815 45.3 40105 ″ >5000 14.8 >5000 27.6 >5000 27.7 12084 Benzyl 38.4 23.7 268.3 97 351.4 78.7 12255 ″ >5000 N/A >5000 N/A >5000 N/A

[0224] As was observed with the LPA1 receptor, the small methyl and methylene amino groups conferred the highest potency at the LPA2 receptor but none of these compounds proved more potent than 1-oleoyl LPA at this site. The LPA3 receptor exhibited much the same profile as the LPA2 receptor as far as efficacies and potencies of compounds relative to LPA are concerned. However, the LPA3 receptor characteristically exhibited higher (1-2 log order) EC50 values for all compounds, including LPA. Presumably, the LPA3 receptor has an intrinsically lower affinity for LPA and LPA analogs. Like the hydrophilic compounds, each LPA receptor showed strong stereoselectivity for a hydrophobic substituent in the R₂ position of Formula I.

[0225] Although saturated ligands were repeatedly found that are active at LPA3, mono-unsaturated compounds were also consistently found that are more potent at this receptor. For example, preliminary results with an 18:1 (oleoyl) analog of SDB-213 suggest that the mono-unsaturated compound is significantly more potent (equipotent to LPA) than the saturated compound at LPA3 in this assay. LPA1 and LPA2 do not exhibit this selectivity for mono-unsaturated vs. saturated acyl groups.

[0226] To investigate an LPA response in a physiologic context, mean arterial blood pressure (MAP), heart rate, and postganglionic sympathetic tone was monitored in anesthetized adult rats as a function of LPA or LPA analog administration. LPA had been shown previously to increase blood pressure transiently in this model. Intravenous injection of three enantiomeric pairs of compounds resulted in a transient increase in MAP with the same pattern of stereoselectivity as observed with the in vitro assays. Concomitant with this rise in MAP was a decrease in heart rate and sympathetic output indicative of baroreceptor reflex response.

[0227] The compounds that were only slightly efficacious at LPA1, e.g. the benzyl-containing VPC12084, were assayed for their ability to antagonize LPA induced GTP[γ 35 S] binding. Although this compound did block LPA activity in the GTP[γ 35 S] binding assay, the benzyl compound (VPC12084) was revealed to posses appreciable agonist activity in assays with greater levels of amplification (e.g., whole cell assays of calcium mobilization or inhibition of cAMP accumulation). In the course of exploring variations of the benzyl substituent, a benzyl-4-oxybenzyl substituent in the same relative configuration (R2: VPC12204) was found to have a reduced, but still measurable, agonist activity in whole cell assays. However, its enantiomer [i.e., VPC12249, the compound with the benzyl-4-oxybenzyl substituent in the S (the R₃ substituent of Formula I) configuration] was completely devoid of agonist activity in the whole cell assays and in the GTP[γ 35 S] binding assay.

[0228] VPC12249 was tested for its ability to block LPA-induced GTP[γ 35 S] binding at each recombinant LPA receptor. As is shown by the rightward, parallel shifts in the concentration response curves as a function of VPC12249 concentration, this compound is a surmountable antagonist at the LPA1 and LPA3, but not the LPA2, receptors (FIG. 6). The KI values for VPC12249 determined by Schild regression are 137 and 428 nM at the LPA1 and LPA3 receptors, respectively, in this assay. The same activity was determined with human LPA1 using a recombinant baculovirus-infected insect Sf9 cell membrane preparation.

[0229] The antagonist activity measured in the broken cell assays was confirmed in whole cell experiments wherein LPA-induced rises in free intracellular calcium in HEK293T cells were blocked. This cell type expresses the LPA1 and LPA3, but not LPA2 receptor genes, as determined by RT-PCR. Increasing concentrations of VPC12249 resulted in parallel, rightward shifts in the LPA concentration response curves (KI 132 nM). The extent of rightward shift observed in the same experimental protocol with A431 cells, which express the LPA2 as well as the LPA1 and LPA3 genes (RT-PCR not shown), was much smaller (KI 1970 nM) as predicted from the lack of antagonist activity of VPC12249 at the calcium-mobilizing LPA2 receptor in the GTP binding assay. The blocking action of VPC12249 was not a general post-receptor event as shown by the lack of antagonism of ATP-evoked calcium transients. Inhibition of forskolin-induced increases in cAMP levels in RH7777 cells stably expressing LPA1 was also inhibited by VPC12249.

Example 3 Synthesis of rac-N-oleoyl-1-hydroxy-propylamide Phosphonic Acid (NOHPP)

[0230] Two batches of NOHPP have been synthesized as a racemic mixture. After observing LPA mimetic activity with the first batch (named JAR1842), the material was re-synthesized, and this batch was named VPC12031. Both batches showed the same profile on thin layer chromatography (TLC) (R_(f) 0.31, chloroform/acetone/methanol/glacial acetic acid/water, 50/15/13/12/4) whereon they migrated as a single, discrete spot. Further, the NMR spectrum of VPC12031 was as expected and the formula weight measured by mass spectrometry (419.5 daltons) agrees with that of the structure. Thus confirming the identity and high degree of purity of the NOHPP sample.

[0231] To assay NOHPP and other compounds at individual LPA receptors, the adapted GTPγS binding assay of Example 3 was used. Briefly, individual, recombinant LPA receptors were express along with heterotrimeric G proteins in HEK293T cells. For the LPA receptor LPA1, which naturally couples to Gi/o proteins, membranes from rat hepatoma cells (RH7777) were also used that have been transfected only with LPA1 DNA. Membranes prepared from these cells are used to measure GTPγ[³⁵S] binding as a function of test compound concentration. The resulting dose-response curves provide relative potency (EC₅₀) and efficacy (E_(max)) for the test compounds. The assay is robust and free of background from the LPA receptors endogenous to HEK293T cells. In FIGS. 2A-C we show the relative activities of LPA and NOHPP at the three known (i.e. cloned) LPA receptors (LPA1, LPA2 and LPA3). NOHPP is distinctly less potent and far less efficacious than LPA at LPA3, but as efficacious as, but somewhat less potent than, LPA at LPA1 and LPA2.

[0232] NOHPP was also tested for activity at the three cloned LPPs. Although the phosphonate head group eliminates the possibility of NOHPP acting as a substrate, it is possible that the compound could be a competitive inhibitor. For the initial assay, 0.1, 1.0 and 10.0 mM NOHPP was tested in competition with 50 nM [³²P]LPA and assayed for the appearance of water soluble radionuclide. As can be seen in FIG. 3, NOHPP inhibited LPP3 and, to a lesser extent, LPP1. NOHPP was inactive in this assay at LPP2.

[0233] The activity of the alpha keto NOHPP analog (VPC12060) at the three LPPs has also been tested. The structure of the alpha keto NOHPP analog is as follows:

[0234]FIG. 4 presents data concerning the inhibition of the three phosphatases (PAP2a, PAP2b and PAP2c (aka LPP1, LPP3, LPP2, respectively) by the alpha hydroxy phosphonate analog of LPA (VPC12031) and the alpha keto phosphonate analog of LPA (w1s060). Both compounds are markedly better at the PAP2b (LPP3) than PAP2a (LPP1) which in turn is better than PAP2c (LPP2). Based on the results of the activity of NOHPP, it is anticipated that analogs of NOHPP will also be active.

Example 4 Synthesis of NOHPP [(9Z)-N-(3-hydroxypropyl)Octadec-9-enamide]

[0235] To a solution of 1-aminopropanol (4.04 ml, 52.8 mmol) and pyridine (4.27 ml, 52.8 mmol) in methylene chloride was slowly added oleoyl chloride (5 ml, 15.1 mmol). After 2 hours, the mixture was diluted with chloroform and washed with ammonium chloride (3×), brine (3×) and dried over sodium sulfate. Column chromatography (15% acetone/chloroform to 50% acetone/chloroform) provided the product as white solid.

[0236] (9Z)-N-(3-oxopropyl)Octadec-9-enamide (22)

[0237] To a suspension of pyridinium chlorochromate (0.477g, 2.21 mmol) and sodium acetate (36 mg, 0.44 mmol) in 10 ml of dichloromethane was cannulated as solution of 1 in 8 ml of dichloromethane. The mixture was stirred for 10 hours, quenched with ether, then filtered through celite and concentrated to an oil. Chromatography in 15% acetone/chloroform provided the product in 47% yield (0.495 g).

[0238] (9Z)-N-{3-[bis(tert-butoxy)Carbonyl]-3-hydroxypropyl}octadec-9-enamide (23)

[0239] To a suspension of sodium hydride in 8 ml of TBF at 0° C. was cannula as a solution aldehyde 3 in 6 ml THF. The mixture was allowed equilibrate to room temperature over an hour. The reaction was quenched with water and acidified with 10% HCl followed by extraction with chloroform (3×). The combined organic extracts were washed with brine (3×) and dried over sodium sulfate. Chromatography in 15% acetone/chloroform provided the product as off-white solid (130 mg, 36%).

[0240] (9Z)-N-(rac-3-hydroxy-3-phosphonopropyl)Octadec-9-enamide (24)

[0241] To a solution of 23 in 1 ml of dichloromethane was added 0.3 ml trifluoroacetic acid. The mixture was stirred for 4 hours (monitored by TLC). Concentration and repeated washings with ether provided the product in 100% yield.

Example 5 Synthesis of w1s-b8L

[0242] 3-(diethoxycarbonyl)propanenitrile:

[0243] In a 50 ml of dry ethanol was added sodium (1.38 g, 60 mmol). After complete dissolution of sodium, diethyl phosphite (7.75 ml, 60 mmol) dissolved in 20 ml toluene was added slowly. After stirring for 1 hour at room temperature, acrylonitrile (3.95 ml, 57 mmol) dissolved in 20 ml toluene was added dropwise over 1 hour. The mixture was allowed to stir overnight. Dilution with water, extraction with CH₂Cl₂ (3×) and drying with sodium sulfate provided a crude yellow oil, which was concentrated and distilled under vacuum (134° C., 1.5 mmHg) to provide the product as clear liquid (6.11 g, 53%).

[0244] (3-aminopropyl)diethoxyphosphino-1-one:

[0245] To a suspension of 3-(diethoxycarbonyl)propanenitrile (2.78 g, 14.5 mmol) and cobalt(ll) chloride (0.378 g, 2.91 mmol) in methanol at −30° C. was added sodium borohydride (5.49 g, 145 mmol) in small portions. The mixture was allowed to equilibrate to room temperature and stirred overnight. Concentrated HCl was added until the black mixture turned blue, which was extracted twice with dichloromethane. The pH of the aqueous phase was adjusted to 9 by addition of concentrated ammonium hydroxide, and the solution was evaporated to dryness to generate pink/blue solid. Concentrated ammonium hydroxide (100 ml) and dichloromethane (200 ml) was added and stirring was continued for 1 hour. Extraction with CH₂Cl₂ (2×), filtration, drying over sodium sulfate, and concentration provided the product as yellow liquid (2.0 g, 70%).

[0246] (9Z)-N-[3-(diethoxycarbonyl)propyl]octadec-9-enamide:

[0247] To a solution of (3-aminopropyl)diethoxyphosphino-1-one (0.736 g, 3.77 mmol) and pyridine (0.61 ml, 7.54 mmol) at 0° C. was slowly added oleoylchloride (1.25 ml, 3.77 mmol) over 20 minutes. The reaction mixture was allowed to warm to room temperature, followed by stirring for another 2 hours. Dilution with ethyl acetate and extraction with saturated aqueous ammonium chloride (3×) and brine (3×), drying over sodium sulfate, and flash chromatography using 15% acetone/chloroform provided the product as off-white solid (0.572 g, 33%).

[0248] (9Z)-N-(3-phosphonopropyl)Octadec-9-enamide:

[0249] To a solution of (9Z)-N-[3-(diethoxycarbonyl)propyl]octadec-9-enamide (0.219 g, 0.48 mmol) in acetonitrile was added trimethylsilylbromide (0.189 ml, 1.43 mmol). The reaction mixture was refluxed for 2 hours and the solvent was evaporated under reduced pressure. Addition of ether and removal in vacuo, a process repeated several times, provided the product as brown solid (0.192 g, 100%).

Example 6 Analysis of w1s-b8L activity

[0250] To assay w1s-b8L at individual LPA receptors, the GTPγS binding assay described in Example 2 was utilized. Briefly, individual recombinant LPA receptors were expressed along with heterotrimeric G proteins in HEK293T cells. Membranes prepared from these cells are used to measure GTPγ(³⁵S] binding as a function of test compound concentration. The resulting dose-response curves provide relative potency (EC₅₀) and efficacy (E_(max)) for the test compounds. w1s-b8L was found to be more potent and efficacious at LPA1 than at either LPA2 or LPA3. Also evident is the lack of receptor-type selectivity by the other phosphonate compounds.

[0251] w1s-b8L and the other phosphonates were also tested also for activity in three whole cell assays. For the LPA receptor LPA1, which naturally couples to Gi/o proteins, rat hepatoma cells (RH7777) were used that have been transfected only with mouse LPA1 DNA. In these cell cultures, drug dependent inhibition of cAMP accumulation was measured. w1s-b8L, was determined to be fully efficacious in this assay at a concentration of 1 μM. At this concentration w1s-b8L is inactive at mobilizing calcium through endogenous receptors LPA receptors expressed by MDA MB-231 cells. Finally, the activity of w1s-b8L in activating a chloride conductance in Xenopus laevis ooctyes was measured. These cells are normally activated by LPA through an endogenous receptor. However, w1s-b8L does not evoke this response. However, when injected with human LPA3 or LPA2 mRNAs a very modest response to w1s-b8L is detected, but only when a concentration of 10 μM is applied to the oocyte surface.

Example 7 Analysis of VPC12249 Effects in a Renal Ischemia-reperfusion Model

[0252] To examine the effect of the compound VPC12249 on renal injury following ischemia-reperfusion (IR) the following experiment was conducted. C₅₇BL6 mice (20 gm, 8 wks of age) were used for all studies. The surgical protocol of renal IR has been previously described (Okusa et al., 1999. Am J. Physiol. (Renal Physiol.) 277: F404-412; Okusa, et al., 2000 Am. J. Physiol. (Renal Physiol.) 279; F809-F818, and Okusa et al., 2001 Kidney Int. 59:2114-2125). For the injury protocol, bilateral flank incisions were made under anesthesia with a regimen that consists of ketamine (100 mg/kg, ip.), xylazine (10 mg/kg, ip.) and acepromazine (1 mg/kg, im.). Renal pedicles were exposed and cross-clamped for 27-32 min. Kidneys were examined for immediate reperfusion following clamp removal. Wounds were closed and mice were returned to cages. Mice were injected with VPC12249 (0.01, 0.1 and 1.0 mg/kg/2 hrs) or vehicle. The mice were sacrificed and the kidneys harvested at 1, 4, 8, 24, 48 hrs, 5 and 7 days. Treatment with VPC12249 or vehicle was initiated 2 hrs prior to ischemia, at the time of reperfusion and every 2 hrs for 4 additional doses. Mice were sacrificed following 24 hrs of reperfusion and plasma was obtained for BUN and creatinine. Plasma creatinine was 1.49±0.26 (n=4), 1.06±0.25 (n=4), 0.45±±0.13 (n=4) and 0.31±0.4 (n=4), for vehicle, VPC12249 0.01, 0.1 and 1.0 mg/kg/2 hrs, respectively. VPC12249 administered at 0.1 (P<0.05) and 1.0 mg/kg/2 hrs (P<0.1) were significantly different compared to vehicle. H and E sections revealed a marked degree of tissue preservation following VPC12249 at 1 mg/kg/2 hr. 

1. A compound represented by the formula:

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, C₈-C₂₂ alkenoyl,

wherein m is 0-20; Z is selected from the group consisting of C₃-C₁₀ cycloalkyl, C₃-C₁₅ bicycloalkyl, C₅-C₁₀ heterocyclic and aryl; R₁₁ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₂₀ alkoxyl, C₁-C₂₀ alkylthio, and C₁-C₂₀ alkylamino; R₂ and R₃ are independently selected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ aLkenyl, C₂-C₄ alkynyl, —(C₁-C₄ aLkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₁₀ alkyl)aryl, C₃-C₈cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₈ alkyl)aryl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ altkynyl)aryl, and

wherein n is 0-10; R₅ is selected from the group consisting of H and C₁-C₄ alkyl; R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆; R₁₃ is selected from the group consisting of H, halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NH₆ and OR₆; wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ aLkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkynyl)R₇; and R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic and optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl; y is 1-4; and R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, α-substituted methylene phosphonate and thiophosphate.
 2. The compound of claim 1 wherein R₁ is selected from the group consisting of

R₁₃ is H; R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate, α-substituted methylene phosphonate and thiophosphate; and y is
 1. 3. The compound of claim 1 wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, and C₈-C₂₂ alkenoyl; R₁₃ is H; and R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate α-substituted methylene phosphonate and thiophosphate; and y is
 1. 4. The compound of claim 3 wherein n is 1; and R₁₂ is selected from the group consisting of SR₆, SOR₆, NHR₆ and OR₆.
 5. A compound represented by the formula:

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl; R₂ is selected from the group consisting of C₁-C₃ alkyl, —(C₂-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —(C₁-C₄ aLkyl)COOR₅, —(C₁-C₄ alkyl)aryl, and

R₄ is selected from the group consisting of hydroxyl, phosphate, methylene phosphonate, α-substituted methylene phosphonate and thiophosphate; R₅ is selected from the group consisting of H and C₁-C₄ alkyl; and R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, and —(C₁-C₄ alkyl)R₇; R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, C₅-C₈ cycloalkenyl and aryl; and y is 1-4.
 6. The compound of claim 5 wherein R₁ is C₁₃-C₁₇alkyl or C₁₇-C₂₁ alkenyl; and R₄ is phosphate, methylene phosphonate or α-substituted methylene phosphonate; and y is
 1. 7. The compound of claim 6 wherein R₂ is selected from the group consisting of C₁-C₃ alkyl, methylene amino, methylene alkyne, phenyl, benzyl, methylene furan, methylene-2-naphthalene, methylene phenol, methylene amino benzyl, methylene phenyl-4-O-benzyl, methylene phenyl-4-benzyl, methylene phenyl-4-chloro, methylene phenyl-4-trans-styrene, methylene phenyl-4-cis-styrene, methylene phenyl-4-O-2,6-dichlorobenzyl and methylene phenyl-4-phenyl.
 8. The compound of claim 6 wherein R₄ is phosphate and R₂ is selected from the group consisting of C₁-C₃ alkyl and benzyl.
 9. A composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier.
 10. An LPA receptor agonist represented by the formula:

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl; R₂ is selected from the group consisting of C₁-C₆ allyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₂-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —(C₁-C₄ alkyl)COOR₅ and aryl; R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate and α-substituted methylene phosphonate; and R₅ is selected from the group consisting of H and C₁-C₄ alkyl.
 11. The LPA receptor agonist of claim 10 wherein the agonist has the general structure:

wherein R₂ is methyl, ethyl, propyl, isopropyl, butyl, methylene amino, methylene alkyne, phenyl, benzyl, methylene furan, methylene-2-naphthalene; and R₄ is hydroxyl (OH), phosphate (PO₄), or methylene phosphonate (CH₂PO₃).
 12. A composition comprising the compound of claim 10 and a pharmaceutically acceptable carrier.
 13. An LPA receptor antagonist represented by the formula:

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₂ is selected from the group consisting of H, C₁-C₄ alkyl; R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate; R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkyl)R₇; and R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, C₅-C₈ cycloalkenyl and aryl.
 14. The compound of claim 13 wherein R₁ is C₁₃-C₁₇alkyl or C₁₇-C₂₁ alkenyl; R₂ and R₃ are H; and R₄ is phosphate, methylene phosphonate or α-substituted methylene phosphonate.
 15. The compound of claim 14 wherein the agonist is represented by the formula:


16. The compound of claim 13 wherein R₂ and R₃ are independently selected from the group consisting of H, benzyl, methylene furan, methylene-2-naphthalene, methylene phenyl-4-O-benzyl, methylene phenyl-4-benzyl, methylene phenyl-4-chloro, methylene phenyl-4-trans-styrene, methylene phenyl-4-cis-styrene, methylene phenyl-4-O-2,6-dichlorobenzyl and methylene phenyl-4-phenyl.
 17. A lyso-lipid phosphate phosphatase resistant LPA analog, said agonist represented by the formula

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, C₈-C₂₂ alkenoyl,

wherein m is 0-20; Z is selected from the group consisting of C₃-C₁₀ cycloalkyl, C₃-C₁₅ bicycloalkyl, C₅-C₁₀ heterocyclic and aryl; R₁₁ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₂₀ alkoxyl, C₁-C₂₀ alkylthio, and C₁-C₂₀ alkylamino; R₂ and R₃ are independently selected from the group consisting of H, hydroxy, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ aLkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, —(C₁-C₄ alkyl)aryl, C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, (C₅-C₁₀ alkyl)aryl, (C₅-C₈ alkenyl)aryl, (C₅-C₈ alkynyl)aryl, and

wherein n is 0-10; R₅ is selected from the group consisting of H and C₁-C₄ alkyl; R₁₂ is selected from the group consisting of halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆; R₁₃ is selected from the group consisting of H, halo, C₁-C₁₀ alkyl, (C₀-C₁₂ alkyl)aryl, (C₂-C₁₂ alkenyl)aryl, (C₂-C₁₂ alkynyl)aryl, —(C₁-C₄ alkyl)OH, —(C₂-C₁₂ alkenyl)OH, SR₆, SOR₆, NHR₆ and OR₆; wherein R₆ is selected from the group consisting of C₁-C₁₆ alkyl, C₂-C₁₆ alkenyl, C₂-C₁₆ alkynyl, —(C₁-C₄ alkyl)R₇, —(C₂-C₄ alkenyl)R₇, —(C₁-C₄ carboxy)R₇ and —(C₂-C₄ alkynyl)R₇; and R₇ is selected from the group consisting of optionally substituted C₃-C₈ cycloalkyl, optionally substituted C₃-C₈ heterocyclic, optionally substituted C₇-C₁₂ bicyclic, optionally substituted C₅-C₈ cycloalkenyl and optionally substituted aryl; q is 1-4; R₈ and R₉ are independently selected from H, hydroxyl, amino, COOH, halo, —PO₃; or R₈ and R₉ taken together form a keto group or a methylene group; and R₁₀ is selected from the group consisting of O, S and NH.
 18. The compound of claim 17 wherein R₁ is selected from the group consisting of

R₁₃ and R₁₀ are H; and q is
 1. 19. The compound of claim 17 wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl, C₈-C₂₂ alkenyl, C₈-C₂₂ alkanoyl, and C₈-C₂₂ alkenoyl; R₁₃ and R₁₀ are H; and q is
 1. 20. The compound of claim 19 wherein n is 1; and R₁₂ is selected from the group consisting of SR₆, SOR₆, NHR₆ and OR₆
 21. A lyso-lipid phosphate phosphatase resistant LPA analog, said agonist represented by the formula

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₂ and R₃ are independently selected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, and

R₅ is selected from the group consisting of H and C₁-C₄ alkyl; and R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkyl)R₇; R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic and C₅-C₈ aryl; R₈ and R₉ are independently selected from the group consisting of H, C₁-C₄ alkyl, and —PO₃, or R₈ and R₉ are combined to form a keto group.
 22. The analog of claim 21 wherein R₁ is C₁₃-C₁₇alkyl or C₁₇-C₂₁ alkenyl; and R₃, R₈ and R₉ are H.
 23. A lyso-lipid phosphate phosphatase resistant LPA receptor agonist represented by the formula:

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₂ is selected from the group consisting of H, hydroxyl, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, —(C₁-C₄ alkyl)COOR₅, and benzyl; and R₉ is selected from the group consisting of H, C₁-C₄ alkyl, halo and —PO₃.
 24. A composition comprising the compound of claim 17 and a phamaceutically acceptable carrier.
 25. A method of enhancing wound repair, said method comprising the steps of contacting the wound with a composition comprising a compound represented by the formula:

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₂ is selected from the group consisting of C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₂-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —(C₁-C₄ alkyl)COOR₅ and benzyl; R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate; and R₅ is selected from the group consisting of H and C₁-C₄ alkyl.
 26. The method of claim 25 wherein R₂ is methyl, ethyl, propyl, isopropyl, butyl, methylene amino, methylene alkyne, phenyl, benzyl, methylene furan, methylene-2-naphthalene; and R₄ is hydroxyl (OH), phosphate (PO₄), methylene phosphonate (CH₂PO₃) or α-substituted methylene phosphonate.
 27. A method of treating a disease characterized by cell hyper proliferation, said method comprising the step of administering to a patient a composition comprising a compound represented by the formula

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate; R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkyl)R₇; and R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, C₅-C₈ cycloalkenyl and aryl, with the proviso that R₂ and R₃ are not both H.
 28. A method of treating reperfusion type injury, said method comprising the step of administering to a patient a composition comprising a compound represented by the formula

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₄ is selected from the group consisting of hydroxyl, phosphate and methylene phosphonate; R₆ is selected from the group consisting of C₃-C₁₆ alkyl, C₃-C₁₆ alkenyl, —(C₁-C₄ alkyl)R₇; and R₇ is selected from the group consisting of C₃-C₈ cycloalkyl, C₃-C₈ heterocyclic, C₇-C₁₂ bicyclic, C₅-C₈ cycloalkenyl and aryl, with the proviso that R₂ and R₃ are not both H.
 29. The method of claim 28 wherein the composition is administered prior to injury to prevent tissue damage.
 30. The method of claim 28 wherein the composition is administered after injury to prevent or limit tissue damage.
 31. A method of inhibiting LPP activity, said method comprising the step of administering a compound represented by the formula

wherein R₁ is selected from the group consisting of C₈-C₂₂ alkyl and C₈-C₂₂ alkenyl; R₂ and R₃ are independently selected from the group consisting of H, C₁-C₆ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, —(C₁-C₄ alkyl)OH, —(C₁-C₄ alkyl)NH₂, —COOR₅, and —(C₁-C₄ alkyl)COOR₅; R₅ is selected from the group consisting of H and C₁-C₄ alkyl; and R₈ and R₉ are independently selected from the group consisting of H, halo, C₁-C₄ alkyl, and —PO₃, or R₈ and R₉ are combined to form a keto group.
 32. The method of claim 31 wherein R₂ is H 